If everything you do needs to work on a three-year time horizon, then you’re competing against a lot of people. But if you’re willing to invest on a seven-year time horizon, you’re now competing against a fraction of those people, because very few companies are willing to do that.
From
Ranking tech companies by revenue per employee - (37signals):

| Rank |
Site |
Employees |
Revenue |
|---|
| 1 |
google |
19,835 |
$23,650,000,000 |
| 2 |
facebook |
1,200 |
$1,100,000,000 |
| 4 |
yahoo |
13,900 |
$6,460,000,000 |
| 11 |
twitter |
175 |
$25,000,000 |
| 21 |
amazon |
24,300 |
$24,510,000,000 |
| 25 |
ebay |
16,400 |
$8,730,000,000 |
| 36 |
craigslist |
30 |
$100,000,000 |
(Revenue figures via Yahoo! Finance except where otherwise linked.)
Finally Amazon did what everyone expected: they launched a self-publishing platform where authors can just upload their e-books and tap into the kindle provisioning platform.
I think we are getting closer to the tipping point between paper and e-ink screens. Amazon seems very well positioned to lead the change as Apple did for music. The biggest market to attack is the university textbook market, which seems still somewhat stuck in the 20th century.
Update: Amazon launches iPhone app to read e-books.